intercalate

To insert an extra leap day into a calendar in order to maintain synchrony with natural phenomena.

'[T]is wonderful where or when we ever got anything of this which we call wisdom, poetry, virtue. We never got it on any dated calendar day. Some heavenly days must have been intercalated somewhere.

At some unknown period, the five days, known to the present time by the names of the five Gathic hymns of Zarathushtra, were intercalated at the end of the twelfth month, to complete the three hundred and sixty-five days of the solar year.

To insert an extra month into a calendar for the same purpose, such as for the Hebrew calendar.

The Sages once overheard three shepherds discussing what weather is characteristic of Adar, and if that weather does not occur, it is not really Adar. As a result, the Sages intercalated the year and added Adar II.

To insert a substance between two or more molecules, bases, cells, or tissues.

To insert anything somewhere (especially between other things), such as an affix into a word. (Compare interpolate.)

... the personal pronouns which form the terminations of the verb, or by an intercalated suffix, the nature and relation of its objects and its subject , and to distinguish whether the object be animate or inanimate, ...

Sometimes f or s is intercalated to lighten the pronunciation : kommen, Kunft ; können, Kunst ; […]

An atom or molecule, or a substance, that enters between the layers of the crystal lattice of another substance, especially that of graphite.

Entry of intercalate molecules from the edge of basal planes of crystallites must be kept sufficiently slow to mitigate mechanical strains..before the intercalate has spread uniformly through any layer.

A compound formed by foreign atoms or molecules entering between the layers of a crystal lattice, especially that of graphite.